In present study total arsenic, inorganic arsenic species and fluoride ion contaminations in underground water of Diplo and Chachro sub district of Tharparkar, Pakistan were investigated. The ...concentrations of total As, inorganic As species, F− and others physicochemical parameters were reported in terms of basic statistical parameters, principal component analysis, cluster analysis, sodium absorption ratio and saturation indices. The As3+ was determined by cloud point extraction using ammonium pyrrolidinedithiocarbamate (APDC) as complexing reagent, and complex was extracted by surfactant-rich phases in the non-ionic surfactant Triton X-114; after centrifugation the surfactant-rich phase was diluted with 0.1 mol/L HNO3 in methanol. While total inorganic arsenic (iAs) was determined by solid phase extraction using titanium dioxide (TiO2) as an adsorbent, after centrifugation, the solid phase was prepared to be slurry for determination. The extracted As species were determined by electrothermal atomic absorption spectrometry. The concentration of As5+ in the water samples was calculated by the difference of the total iAs and As3+, while F− and other anions were determined by ion chromatography. The positive correlation of F− and As species with Na+ and HCO3− showed that the water with high salinity and alkalinity stabilized the As species and F− in the groundwater. The positive correlation (r = 0.640, p = 0.671) was observed between total As and it species with F−. Results showed that underground water samples of these two areas of Tharparkar were severely contaminated with arsenic and fluoride ion, which are exceeded the World Health Organization (WHO) provisional guideline value, and United States Environmental Protection Agency, maximum contaminant level of 0.01 mg/L and 1.5 mg/L, respectively.
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► Simultaneously evaluated the contamination of F− and arsenic in underground water. ► Speciation of arsenic by cloud point and solid phase extraction methods. ► Application of multivariate statistical methods for groundwater quality assessment. ► Correlation of As and F− with other physicochemical parameters was carried out.
In this study, the MGO@SnO as a new nanocatalyst with diverse chemical/physical properties was generated by the combination of graphene oxide covered with magnetic iron oxide (MGO) and tin oxide ...(SnO(x)) nanoparticles used for biodiesel production from soybean oil. Before GC-FID analysis, the nanostructured MGO@SnO was successfully employed to transesterify soybean oil to FAMEs (biodiesel). The proposed material was characterized using Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy-dispersive X-ray spectrometer (EDX), X-ray diffraction (XRD), and vibrating sample magnetometer (VSM). Given the acidic-alkaline nature of the proposed catalyst, it has a strong probability of creating carbocation ions to attack with methanol and subsequently converting the triglycerides to methyl ester (FAMEs). In further experiments, it was found that the ideal reaction parameters were a ratio of MGO to SnO of 1:0.5, a molar ratio of soybean oil to methanol (MeOH) of 1:10, a reaction period of 180 min, and a reaction temperature of 120 °C. Furthermore, the MGO@SnO catalyst demonstrated adequate catalytic performance (>88 %) for transforming the triglycerides of soybean oil to FAMEs (biodiesel) as compared to pure SnO NPs (74 %) and plain MGO (69 %) at similar conditions.
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•Novel functionalized magnetic sporopollenin (MPSP) as an efficient sorbent.•Stir bar sorptive dispersive microextraction (SBSDME) as a facile technique.•Combination of SBSDME with ...MPSP for determination of trace levels of melamine.•Successful application of the method in milk based food products as complex matrixes.
The novel green magnetic phosphonated-functionalized sporopollenin nanocomposite (MPSP-nanocomposite) was synthetized and used for stir bar sorptive dispersive microextraction (SBSDME) of melamine in milk and milk-based food products. TEM, SEM-EDX, FT-IR, VSM techniques were applied for characterization of MPSP-nanocomposite. The influential parameters including pH, extraction time, stirring rate, elution solvent type and volume, sample volume, desorption time, and ionic strength were studied and at optimum conditions, the linear range of 1–500 (µg L−1), the LOD (S/N = 3) of 0.30 (µg L−1), and the LOQ (S/N = 10) of 0.95 (µg L−1) were achieved. The intra-day precision values (RSD (%), n = 7) of 3.5% for the melamine concentration of 25 (µg L−1). The relative recoveries of 95.8% to 99.6% were acquired for the real samples which confirmed that the proposed method could be successfully utilized in complex matrixes with high matrix effects.
In the present study, silver (Ag), cadmium (Cd), nickel (Ni), cobalt (Co) and lead (Pb) were simultaneously determined in water samples of fresh water canal receiving untreated effluents from an ...industrial area, of Sindh Pakistan. The analytes in the water sample were determined by CPE using ammonium pyrrolidinedithiocarbamate (APDC) as a complexing agent and then entrapped in non-ionic surfactant, octylphenoxypolyethoxyethanol (Triton X-114). The surfactant rich phase was diluted with acidic ethanol prior to analysis by flame atomic absorption spectrometry. The variables affecting the complexation and extraction steps such as pH of sample solution, concentration of oxine and Triton X-114, equilibration temperature and time period for shaking were investigated in detail. The validation of the procedure was carried out by analysis of a certified reference sample of water (CRM1634e). Reliability of the proposed method was also checked by the standard addition method in a real sample at three concentration levels of all metals. Under the optimum conditions, the preconcentration of 10mL sample solutions, allowed preconcentration factor of 20-fold. The lower limit of detection obtained for Ag, Cd, Ni, Co and Pb was 0.42, 0.48, 0.92, 0.62, and 1.42μgL−1, respectively. The proposed procedure was successfully applied to waste and fresh water samples for simultaneous determination of different metals. The concentration of Ag, Cd, Ni, Co and Pb has shown a decreased trend from 46.5–6.96, 23.0–8.92, 30.2–12.8, 14.2–4.45 and 15.3–5.32μgL−1, respectively from initial entrance of waste water along the downstream of canal.
The present study investigated total arsenic (tAs), inorganic arsenic (iAs) species and fluoride ion (F−) contamination in underground water of Mithi and Nangarparkar subdistricts of Tharparkar, ...Pakistan. Statistical parameters, principal component analysis, cluster analysis, sodium absorption ratio and saturation indices (SI) were used to detect interrelation and sources of concentration of tAs, iAs species (As3+ and As5+), F− and others physicochemical parameters. The concentration of As3+ was measured by cloud point extraction using ammonium pyrrolidinedithiocarbamate (APDC) as complexing reagent, while inorganic arsenic (iAs) was determined by solid phase extraction, using titanium dioxide. The positive correlation was observed between F− contents with As species and other major ions, found in the underground water of the study area. The resulted data indicated that underground water samples of two areas of Tharparkar were severely contaminated with arsenic (0.100–3.83mg/L) and fluoride ion (13.8–49.3mg/L), which were exceeded the World Health Organization provisional guideline values, 0.01mg/L and 1.5mg/L, respectively. The SI of fluorite and calcite in the underground water samples showed that most of the samples were oversaturated with respect to calcite and fluorite.
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► Simultaneous contamination of underground water with arsenic and fluoride. ► Total, and inorganic arsenic species were determined by advance extraction methods. ► Statistical method used for water quality management with respect to geological effect. ► Correlation of As, F and saturation index with other physico chemical parameters. ► For irrigation and industrial water quality assessment SAR and SI were determined.
Humans are exposed to arsenic (As) through air, drinking water, and food. The arsenic (As) hazardous quotient was calculated on the basis of its concentration in drinking water of different origin ...and scalp hair of male subjects (nâ=â313), residents of different exposed and non-exposed areas of Sindh, Pakistan. The total As was determined in water and scalp hair samples, while As species were determined in water samples by advance extraction methodologies. The total As concentrations in drinking water of less-exposed (LE) and high-exposed (HE) areas was found to be 2.63 to 4.46 and 52 to 235, fold higher than the permissible limit, respectively, than recommended by World Health Organization (2004) for drinking water. While the levels of As in drinking water of non-exposed (NE) areas was within the permissible limit. The resulted data indicated that the dominant species was Asâºâµ in groundwater samples. The levels of As in scalp hair samples of male subjects of two age groups (18â30 and 31â50 years), belonging to NE, LE, and HE areas, ranged from 0.26 to 0.69, 0.58 to 1.34, and 15.6 to 60.9 μg/g, respectively. A significant correlation between As levels in drinking water and scalp hair was observed in HE area (râ=â0.86â0.90, pâ
The extent to which smokeless tobacco endangers human health is an ongoing subject of debate. In this study, concentrations of toxic metals, cadmium (Cd), lead (Pb), and nickel (Ni), were measured in ...different snuff products (dry brown and black and moist green and brown), available and consumed in Pakistan. Concentrations of Cd, Pb, and Ni were determined in 23 samples of various brands of snuff by electrothermal atomic absorption spectrometry, after microwave-assisted acid digestion. The reliability of methodology was assured by analyzing certified reference material. The resulted data of toxic metals in different snuff products are comparable to the existing information with limited exceptions. It was estimated that 10 g intake of different types of snuff could contribute 14–68, 17–47, and 20–73 % of the provisional maximum tolerable daily intake for Cd, Ni, and Pb, respectively.
Simultaneous removal of fluoride (F−), inorganic arsenic species, AsIII and AsV, from aqueous samples has been performed using an economic indigenous biosorbent (Stem of Tecomella undulata). The ...inorganic As species in water samples before and after biosorption were determined by cloud point and solid phase extraction methods, while F− was determined by ion chromatography. Batch experiments were carried out to evaluate the equilibrium adsorption isotherm studies for AsIII, AsV and F− in aqueous solutions. Several parameters of biosorption were optimized such as pH, biomass dosage, analytes concentration, time and temperature. The surface of biosorbent was characterized by SEM and FTIR. The FTIR study indicated the presence of carbonyl and amine functional groups which may have important role in the sorption/removal of these ions. Thermodynamic and kinetic study indicated that the biosorption of AsIII, AsV and F− were spontaneous, exothermic and followed by pseudo-second-order. Meanwhile, the interference study revealed that there was no significant effect of co-existing ions for the removal of inorganic As species and F− from aqueous samples (p > 0.05). It was observed that the indigenous biosorbent material simultaneously adsorbed AsIII (108 μg g−1), AsV (159 μg g−1) and F− (6.16 mg g−1) from water at optimized conditions. The proposed biosorbent was effectively regenerated and efficiently used for several experiments, to remove the AsIII, AsV and F− from real water sample collected from endemic area of Pakistan.
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•Simultaneously removal of fluoride and arsenic from water by green technology.•SEM and FTIR studies indicated the sorption of fluoride and inorganic arsenic species.•Kinetic and isotherm sorption study were used to design large scale removal method.•Thermodynamic study stated the process of sorption was exothermic and spontaneous.
Smokeless tobacco (SLT) has been associated with oral cancer. In present study, the total and artificial saliva extracted toxic elements (TEs), arsenic (As), cadmium (Cd), nickel (Ni) and lead (Pb) ...were estimated in SLT products (gutkha, green and brown snuff). Dual-cloud point extraction has been used for the preconcentration of As, Cd, Ni and Pb in artificial saliva extract, using complexing reagent, ammonium pyrrolidinedithiocarbamate. The dual-cloud point extraction procedure was based on forming complexes of elemental ions with complexing reagent and subsequent entrapping of the complexes in nonionic surfactant. Then the surfactant rich phase containing the complexes was treated with nitric acid, and detected ions were back extracted again into aqueous phase at the second cloud point extraction stage, and finally determined by electrothermal atomic absorption spectrometry. The validity of methodology was tested by simultaneously analyzing certified reference material and spike recovery test. The experimental enhancement factors of As, Cd, Ni and Pb were found to be 52, 58, 48 and 44, respectively. The concentration of As, Cd, Ni and Pb in artificial saliva extracts corresponds to 18–24, 45–75, 30–55, and 20–30%, respectively, of the total contents of TE in different types of SLT products (gutkha, brown and green snuff). It was estimated that 10g intake of SLT products (gutkha, brown and green snuff) could contribute 2.2–13, 21–69, 3.4–48 and 10–75% of the provisional maximum tolerable daily intake of As, Cd, Ni and Pb, respectively for adults ~60kg.
•Lack of knowledge about toxic elements (TEs) in smokeless tobacco (SLT) needs to be investigated.•The total and artificial saliva extracted TEs in SLT products were accomplished.•The TEs in artificial saliva extract of SLT were immediately available to consumers.•Long-term use of SLT generates free radicals which promote oral cancer.
In this study, magnetic sporopollenin supported cyanocalixarene (MSP-CyCalix) nanocomposite was synthesized and introduced as an adsorbent material for the removal of pesticides from aqueous media. ...MSP-CyCalix was characterized by different analytical techniques FTIR, SEM, EDX, BET, VSMand TEM. Chlorpyrifos and hexaconazole pesticides were chosen as model analytes solutions for testing the adsorption efficiency of MSP-CyCalix adsorbent. The adsorption results showed that the incorporated cyano functional groups significantly increased the chemical reactivity and adsorption capacity for pesticides. To obtain the highest possible performance, experimental parameters such as pH, salt, dosage and time were optimized. Adsorption kinetics and isotherms models showed that pesticide adsorption process was well fitted with the pseudo-second-order and Langmuir models with a maximum adsorption capacity of 13.88 mg g−1 and 12.34 mg g−1 and a removal efficiency of >90% for both pesticides. Lastly, MSP-CyCalix maintained a removal efficiency of >80% for ten cycles and 60% after the eleventh cycles of usage. The results proved that MSP-CyCalix nanocomposite can be used as an efficient adsorbent for the removal of pesticide residues from water.
•Synthesis and characterizations of new green and honey-comb like cyno-substituted calix-based magnetic sporopollenin.•Removal behavior investigations of the new magnetic adsorbent for pesticides.•Optimization of parameters to evaluate removal performance of the MSP-CyCalix.•Pesticides adsorption on nanocomposite was fitted by Langmuir model.
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